1. Field of the Invention
The present invention relates to a dry-processing apparatus for dry-processing objects to be dried such as foods, industrial materials, garbage, and industrial waste, and in particular to a dry-processing apparatus relatively small in size, convenient and sanitary in use for heat-drying raw garbage, foodstuff, feedstuff and powdered materials generated in kitchens or hospitals and other waste having a relatively high moisture content.
2. Description of the Prior Art
As a means to solve environmental problems on our Earth, waste disposal techniques for processing household garbage or industrial waste materials are beginning to draw people's attention. Conventional waste disposal devices range from a mechanical processing machine called a disposer to an incinerator which uses gas fuels or liquid fuels. The mechanical processing machines process garbage by shredding it with rotating blades and then by disposing of the shredded garbage in a local drainage system. The incinerators process garbage by using burners to heat and burn the garbage to ashes. Another waste disposal device available is one which employs microwave radiation.
Such conventional devices, however, suffer from the following disadvantages. The mechanical processing machines are capable of reducing garbage in its size. Disposing of shredded garbage into the drainage system, however, greatly increases the percentage of a solid waste within the drainage system, possibly causing the local drainage system to clog. This is often an issue facing local governments. On the other hand, the disadvantages of the incinerators is that they are bulky and complex in structure, because they need gas fuels or liquid fuels. Although the waste disposal device which uses microwaves to burn garbage is free from the above-mentioned disadvantages such as drainage system clogging and bulky and complex structure, the microwave disposal device exhibits poor emission characteristics (inadequate for household application) and causes condensation as a result of moisture contained emissions. Such emissions may contaminate or damage the ambient environment of any facility where the microwave disposal device is installed. The present invention overcomes the above described disadvantages presented by the microwave disposal device.
In the meantime, a method of drying food has been widely accepted for preserving food for a long period of time. Among other methods, hot-air drying, drying by microwave heating, freeze drying, and spray drying are widely used, and are now playing an important role in long-term preservation of food. Like dried food, household garbage may be easy to handle once it is dried and dehydrated.
In a heat-drying operation, liquids separated are normally emitted as a gas such as a vapor into the ambient air. In some cases, vapor is condensed along with odors in a manner that keeps the odors entrapped. Such a process is typically applied to a large-scale cooling device, such as a cooling plant, which is equipped with a drying block and a condensation block on a separate basis. Such separate construction is not suited to a small-scale design.
Electric-powered drying methods applied to small-scale designs typically involve contact heating by heaters or non-contact heating by microwave radiation. In contact heating by heaters, non-uniform heating and then non-uniform drying take place, thereby decomposing an object to be dried, and developing odors. The microwave heating suffers the same disadvantages as those of the contact heating, because it is difficult to uniformly distribute the microwave electric field intensity.
In a conventional rotating type heat-drying apparatus, although the drying progresses successfully while the drying objects are still wet by virtue of a good heat transfer, as the moisture thereof decreases, the heat transfer will become worse such that the drying will require a longer time period and moreover the drying objects disadvantageously adhere to the rotating basket.
Moreover, the heat sources employed in dry-processing apparatuses are, for example, of an electric heater type, a combustion heat type, a microwave type, and the like. The electric heater type apparatus has advantages in safety and controllability, but generates a significant heat loss which makes it difficult to increase the drying efficiency. The combustion heat type dry-processing apparatus uses a gas fuel, liquid fuel, or the like, which results in a complicated large-size apparatus accompanied by deficiency in safety. In contrast to the above-mentioned types, since the microwave type drying apparatus has a high drying efficiency because the microwaves are selectively absorbed in moisture contained in the drying objects, no complication nor increase in size of the apparatus itself results, for which reason the microwave type is appropriate for dry-processing drying objects having a high moisture content.
However, such a conventional microwave type drying apparatus has the following problems. Since microwaves tend to have an uneven intensity distribution, it is difficult to effect a uniform dry-processing of objects and, practically, the drying objects located at lower positions remain wet even when the drying apparatus is finished processing them. Particularly when the drying object is garbage, boiled liquid of the garbage remains in the lower portion and is unsanitary.
Furthermore, vapor generated from the drying objects is condensed into dew after the drying objects are removed, which results in contamination of the inside and outside of the drying chamber. If microwaves are continuously applied to the drying objects after the drying objects are dried, the drying objects may catch fire and cause danger. Accordingly, the object of the present invention is to provide a microwave type drying apparatus capable of achieving a high condensation of vapor generated from the drying objects while reducing the volume of the drying objects with sufficient sanitation.
Whereas the garbage, as described above, should be stored until the specified time to collect it and near the place where it is created, it will form an environment in which the garbage is itself likely to decompose due to its large moisture content. As a result, a first great problem has been that the decomposition progresses during the storage of garbage and generates a fowl odor. A second great problem has been that garbage increases in weight due to its large moisture content so as to make a heavy burden of conveying the packs, in which the garbage is accommodated, to the specified place where they are collected. Also, it is very often the case that the moisture will leak out of the packs, in which garbage is collected, during the conveyance of the packs up to the collecting place, in which case the remainder will cause a secondary odor to occur. The solution to this problem has been urgently expected, especially by those living in collective housing.
As viewed with respect to the foregoing problems, conventional garbage disposing apparatus, although capable of crushing garbage into minute pieces, cause great amounts of solid and organic components to be included in the drainage which appears after the disposal of garbage, and which accounts for organic pollution of rivers and the like. The incinerating system has not yet solved problems including the generation of odor during the incineration, and processing of ashes that are difficult to dispose. Also, the drying system, capable of reducing the weight of garbage and making it free of decomposition, has nonetheless had difficulties in uniformity of drying, power consumption, processing of vapor and odor to be generated.
Accordingly, with the conventional methods having their peculiar problems as described above, it can be said that we have up to now had no sufficiently small sized garbage disposing apparatus that can serve for practical uses. It has been demanded to realize this aim.